WASHINGTON  The United States has decided to reimburse Pakistan $688 million for the cost of providing support for some 140,000 troops on the border with Afghanistan.

Deputy Defense Secretary Ashton Carter notified Congress that the U.S. would make the payment to Islamabad for expenses incurred from June through November 2011.

“In making this determination, I find that the reimbursement is consistent with the national security interest of the United States and will not adversely affect the balance of power in the region,” Carter wrote in the Dec. 6 letter.

Lawmakers have expressed frustration with Pakistan, questioning its commitment in the fight against terrorism and using the foreign aid budget to punish Islamabad. The anger boiled over after the killing of Osama bin Laden in Pakistan in May 2011, with suggestions that the country was harboring the terrorist leader.